All of the sources are a good way of learning, but it depends entirely on what you are trying to learn.
There are many times when books do not suffice and being able to talk to someone who has experience in the matter is invaluable (such as learning to drive a car).
In certain situations, watching someone do something is the best method, whether you are there or watching a video (such as replacing the fender on the car you smashed up practicing driving).
You also must remember that "knowing how to do something" does not equate to "being good at it".
That is where hands-on experience and practice are what you need to advance your skill.
Being a good teacher is an ability you have, or you don't. You can't teach someone to be a good teacher.
I taught my first wife doctoral level statistics and she got a higher grade in the class than her college professor (who was her mentor) did when he took the class.
I've never had a class in statistics ... but I can teach.